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My customer just called to ask if we can comply to A239. What does that entail?

ASTM A239 is commonly called the Preece Test. The official name is Standard Test Method for Locating the Thinnest Spot in a Zinc (Galvanized  Coating on Iron or Steel Articles by the Preece Test (Copper Sulfate Dip). It is used primarily for hardware items such as nuts and bolts. It is impractical for structural steel items because of the testing solutions and handling that would be required. It has no precision because of the many possible operator techniques (Section 11.1). Compliance with A239 is technically possible. A cost of $50-100,000 for tanks, chemicals, disposal, and re-galvanizing makes samples impractical. The test destroys the coating on the tested sample.

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I am looking for a solution for our products to pass the preece test since in certain cases the test passes and in others it does not and this happens under the same conditions Could you help me another point the bottom dross at what temperature does it begin to float and this can interfere with the intermetallic layers Thank you


Hello Jesus, Preece test is not recommended for hot-dip galvanized steel. Preece testing attacks the wrong material (zinc metal instead of the self-protecting zinc patina it develops), and therefore will give an incorrect prediction of the performance of the hot-dip galvanized coating in the real world. Instead, the best method to predict the performance of hot-dip galvanized steel in various environments is to look at its performance using real world case studies spanning over 100 years of corrosion data. This performance daata is all provided for free on our website. Regarding bottom dross, this information is only available to AGA members only. Please contact us about becoming a member.

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